Title of Invention

AN AUTOMATIC TRANSMISSION FOR MOTOR VEHICLE

Abstract A powertrain having a torque converter, friction input shifting clutches and shared driving gears has an axially compact design, packages a transmission pump between the torque converter and a clutch hub and achieves seven forward speed ratios utilizing four back-to-back synchronizers.
Full Text POWERTRAIN WITH TORQUE CONVERTER AND AXIALLY COMPACT
SEVEN SPEED DUAL CLUTCH TRANSMISSION
CROSS REFERENCE TO CO-PENDING APPLICATION
[0001] This patent application is a continuation-in-part of patent application
Ser. No. 11/466,479, filed on August 23, 2006, now
TECHNICAL FIELD
[0002] The invention relates to a powertrain having a power source, a
torque converter and a compact seven speed transmission with two friction shifting
clutches.
BACKGROUND OF THE INVENTION
[0003] Dual clutch transmissions (DCTs) have been designed with friction
launch clutches that connect the output of a torque converter to a lay shaft
transmission. Dual clutch transmissions are known for their sporty,
performance-oriented characteristics. Dual clutch transmissions typically exhibit
good fuel economy due to good gear mesh efficiency and ratio selection flexibility.
Synchronizers are typically used to engage gears with the countershafts to
complete power flow from the engaged input clutch to an output shaft. The
synchronizers have low spin losses; thus, overall operating efficiency is enhanced.
However, dual clutch transmissions have some specific design considerations. For
example, due to the high heat that can be generated during slip, the shifting
clutches must be of a relatively large size. Shudder and oil life durability must
also be addressed. Furthermore, cooling circuits for the friction shifting clutches
are typically relatively complex due to the heat dissipation requirements of these
large clutches. Finally, because lay shaft or countershaft transmissions typically
have many sets of axially-aligned, intermeshing gears, the overall axial length of
countershaft transmissions may limit there use in some vehicle designs.
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SUMMARY OF THE INVENTION
[0004] A powertrain having a torque converter and dual shifting friction
clutches connectable to first and second concentric intermediate shafts combines
the smoothness and ratio-boosting effects of a torque converter with the low spin
losses associated with synchronizers used in dual clutch designs, while preferably
providing seven fixed forward speed ratios in an axially compact design. Several
aspects of the powertrain contribute to the minimization of axial length. For
example, driving gears connected for common rotation with the intermediate shafts
intermesh with driven input gears connectable for rotation with each of the
respective countershafts, thus functioning as shared driving gears. Preferably,
back-to-back synchronizer pairs are supported on the countershafts between
adjacent intermeshing aligned gear sets such that only four back-to-back
synchronizer pairs are necessary and only four synchronizer selection devices are
required to control engagement of the four pairs. Additionally, a parking gear is
preferably connected for common rotation with one of the countershafts such that
it is radially-aligned with an intermeshing output gear set. (A radial plane is in a
plane encompassing radii of the driving or driven gears, perpendicular to the axis
of rotation of the input member, output member, intermediate shafts and
countershafts in the transmission. Accordingly, as used herein, components that
are "radially-aligned" are aligned in a radial plane.) Furthermore, positioning of a
transmission oil pump between the torque converter and the first and second
friction shifting clutches allows a clutch hub supporting the friction shifting
clutches to be configured with clutch hub passages for routing oil delivered from
the pump to the friction shifting clutches.
[0005] Specifically, within the scope of the invention, the powertrain
includes a power source and a torque converter that operatively connects the power
source with a transmission input member. First and second friction shifting
clutches are alternately selectively engagable to operatively connect the
transmission input member with first and second concentric intermediate shafts,
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respectively. A first input driving gear is connected for common rotation with the
first intermediate shaft and intermeshes with a first pair of driven input gears that
are each connectable for common rotation to a different respective one of the
countershafts to selectively transfer torque to the respective countershaft when the
first friction input clutch is engaged. Furthermore, a second input driving gear is
connected for common rotation with the second intermediate shaft and intermeshes
with a second pair of input gears each connectable for common rotation with a
different respective one of the countershafts to selectively transfer torque to the
respective countershaft when the second friction input clutch is engaged. Thus,
when torque is provided through either of the friction clutches to the countershafts,
shared driving gears on each of the countershafts transfer the torque to one of the
countershafts, depending on synchronizer engagements. Preferably, the first
countershaft includes two input driving gears and the second countershaft has two
other input driving gears so that four intermeshing aligned gear sets are used for
input of torque from the first and second friction shifting clutches. Preferably two
output gear sets are utilized, including a first output gear set that has a first output
driving gear connected for common rotation with the first countershaft and a first
output driven gear connected for common rotation with the output member that
continuously intermeshes with the first output driving gear. Similarly, the second
output gear set has a second output driving gear connected for common rotation
with a second countershaft and a second output driven gear connected for common
rotation with the output member that continuously intermeshes with the second
output driving gear. Accordingly, the input and output driving gears and the input
and output driven gears thereby form six sets of intermeshing aligned gears. By
utilizing the four back-to-back synchronizers and selectively engaging the friction
shifting clutches, seven forward speed ratios and a reverse speed ratio are
achieved.
[0006] Unique packaging of the transmission oil pump allows simplified
routing of clutch and lubrication oil and compact piloting of a clutch hub that
supports the dual friction shifting clutches. Specifically, the clutch hub is
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configured with clutch hub passages for routing oil delivered from the transmission
oil pump to the first and second friction shifting clutches. Preferably, a stationary
clutch hub support member at least partially supports the clutch hub and is
configured with clutch hub support member passages that are in fluid
communication with the clutch hub passages so that oil may be routed from the
transmission oil pump to the friction shifting clutches through the stationary clutch
hub support member. The transmission oil pump is preferably radially-inward of
and partially surrounded by the stationary clutch hub support member. Preferably,
a stator support shaft connects a stator portion of the torque converter with the
clutch hub support member. The oil pump is positioned radially-outward of the
stator support shaft. Preferably the stator support shaft is configured with stator
support shaft passages that are in fluid communication with the oil pump to route
oil delivered from the oil pump to the torque converter.
[0007] The above features and advantages and other features and advantages
of the present invention are readily apparent from the following detailed description
of the best mode for carrying out the invention when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIGURE 1 is a schematic illustration of a first embodiment of a
powertrain with an engine, a torque converter, a transmission with dual friction
shifting clutches, and an oil pump positioned between the torque converter and the
friction shifting clutches;
[0009] FIGURE 2 is a table showing an engagement schedule of the
friction shifting clutches and synchronizers in the powertrain of Figure 1 to
achieve seven forward speed ratios and a reverse speed ratio; and
[001.0] FIGURE 3 is a partial schematic fragmentary illustration of the
torque converter, oil pump and friction shifting clutches of the powertrain of
Figure 1, showing a clutch hub, a clutch hub support member and a stator shaft
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support member that enable routing of oil from the oil pump to the torque
converter and to the friction shifting clutches.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Referring to the drawings, wherein like reference numbers represent
the same or corresponding parts throughout the several views, there is shown in
Figure 1 a powertrain 10 for a vehicle (not shown). The powertrain 10 includes a
power source or engine 14, a torque converter 16 and a transmission 18. The torque
converter 16 includes a turbine portion 20, a pump portion 22, and a stator portion
24. An engine output shaft 23 is connected for rotation with a hub member 25 that
is connected to the pump portion 22. The turbine portion 20 is connected with a
transmission input member 26. A fluid coupling between the pump portion 22 and
the turbine portion 20 thus operatively connects the engine 14 with the transmission
input member 26. The transmission input member 26 is preferably in the nature of a
shaft. Selective engagement of a torque converter clutch 28 allows the engine 14 to
be directly connected with the input member 26, bypassing the torque converter 16.
Preferably, the torque converter clutch 28 is electronically controlled and may be
enhanced with a plurality of clutch plates to provide a large clutch torque capacity,
thus making the converter clutch 28 able to transmit a large amount of torque. The
stator portion 24 is grounded to a stationary member, such as the transmission
housing 30, through a typical one-way clutch 32. A damper 34 is operatively
connected to the torque converter clutch 28 for absorbing vibration. A transmission
oil pump 36 is operatively connected for rotation with the pump portion 22. Support
for the pump 36 and fluid communication from the pump 36 to the transmission 18
and to the torque converter 16 will be discussed hereinafter. Briefly, a stator support
shaft 38 supports the stator and is located radially-inward of the pump 36. The
stator support shaft 38 operatively supports the stator portion 24 and is connected
with a stationary clutch hub support member 40 that is grounded to the transmission
housing 30. A clutch hub 42 operatively connects the input member 26 with first
and second concentric intermediate shafts 44, 46 by selective engagement of first
and second friction shifting clutches CO and CE, respectively.
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[0012] The transmission 18 further includes a first countershaft 50 and a
second counter shaft 52 which are axially-spaced from and generally parallel with
the intermediate shafts 44 and 46.
[0013] Six aligned, intermeshing gear sets are utilized to transfer torque from
the intermediate shafts 44, 46 via the countershafts 50, 52 to an output member 56
(preferably in the form of a shaft) to establish multiple speed ratios between the
input member 26 and the output member 56. The output member 56 is connected to
a final drive mechanism 58 which may be connected to vehicle wheels (not shown).
[0014] A first intermeshing gear set includes gears 60, 62 and 64. The gear
60 is a shared input driving gear that is connected for common rotation with the
intermediate shaft 44 and continuously intermeshes with both gears 62 and 64. The
gear 62 is rotatable about the first countershaft 50 and is selectively connectablc
therewith. The gear 64 is rotatable about the second countershaft 52 and is
selectively connectable therewith.
[0015] A second intermeshing gear set includes gears 66, 68 and 70. The
gear 66 is connected for common rotation with the intermediate shaft 44 and
continuously intermeshes with both gears 68 and 70. The gear 68 is rotatable about
and selectively connectable with the countershaft 50. The gear 70 is rotatable about
and selectively connectable with the second countershaft 52.
[0016] A third intermeshing gear set includes gears 72, 74 and 76. The gear
72 is connected for common rotation with the intermediate shaft 46 and
continuously intermeshes with both gears 74 and 76. The gear 74 is rotatable about
and selectively connectable for rotation with the first countershaft 50. The gear 76 is
rotatable about and selectively connectable for rotation with the second countershaft
52.
[0017] A fourth intermeshing gear set includes gears 78, 80, 82 and a gear
84. The gear 78 is connected for common rotation with the intermediate shaft 46.
The gear 78 continuously intermeshes with both the gear 80 and the gear 82. The
gear 82 continuously intermeshes with the gear 84. The gear 80 is rotatable about
and selectively connectable for common rotation with the first countershaft 50. The
gear 82 is an idler gear supported on a separate axis I. The gear 84 is rotatable about
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and selectively connectable with the second countershaft 52. The gears 60, 66, 72
and 78 are referred to herein as input driving gears. The gears 62, 64, 68, 70, 74, 76,
80, and 84 are referred to herein as input driven gears.
[0018] The transmission 18 includes a fifth intermeshing, aligned gear set
that includes a gear 86 and a gear 88. The gear 86 is connected for common rotation
with the second countershaft 52 and continuously intermeshes with the gear 88
which is connected for common rotation with the output member 56. A sixth
intermeshing, aligned gear set includes gear a 90 which is connected for common
rotation with the first countershaft 50 and a gear 92 which is connected for common
rotation with the output member 56 and continuously intermeshes with the gear 90.
The gears 86 and 90 are referred to herein as output driving gears and the gears 88
and 92 arc referred to herein as output driven gears. The intermeshing, aligned gear
set including the gears 60, 62 and 64 may be referred to as a first input gear set. The
intermeshing, aligned gear set including the gears 66, 68 and 70 may be referred to
as a second input gear set. The intermeshing, aligned gear set including the gears
72, 74 and 76 may be referred to a third input gear set. The intermeshing, aligned
gear set including the gears 78, 80, 82 and 84 may be referred to herein as a fourth
intermeshing gear set. The gear set including the gears 90, 92 may be referred to as
a first output gear set and the gear set including the gears 88 and 86 may be referred
to as a second output gear set. The four input gear sets utilize shared input driving
gears: the gear 60, the gear 66, the gear 72 and the gear 78. Each of the input
driving gears 60, 66, 72 and 78 intermesh with gears that are connectable for
rotation with each of the countershafts 50, 52. Thus, the shared input driving gears
are each able to transfer torque to both of the countershafts 50, 52, the countershaft
to which torque is transferred being dependent on the engagement of synchronizers,
as will be described herein.
[0019] A parking gear 94 is radially-aligned with the output gear set 90, 92.
Thus, the parking gear 94 is situated in what may otherwise be unused, empty space
and docs not require any addition to the axial length of the transmission 18.
[0020] The transmission 18 includes four pairs of back-to-back
synchronizers: A, B, C and D. The back-to-back synchronizer pair A includes
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synchronizer A1 and a synchronizer A3. The synchronizer A1 is selectively
engagable to connect the gear 64 for common rotation with the second countershaft
52. The synchronizer A3 is selectively engagable to connect the gear 70 for
common rotation with the second countershaft 52. A single synchronizer selection
device 96 is operable to engage either the synchronizer Al or A3. Specifically, a
synchronizer selection device 96 is shiftable to the left to engage the synchronizer
Al and shiftable to the right the engage the synchronizer A3.
[0021] The back-to-back synchronizer pair B includes a synchronizer B2 and
a synchronizer BR. The synchronizer B2 is selectively engagable to connect the
gear 76 for common rotation with the second countershaft 52. The synchronizer BR
is selectively engagable to connect the gear 84 for common rotation with the second
countershaft 52. A single synchronizer selection device 98 is operable to control
engagement of both the synchronizer B2 and the synchronizer BR. Specifically, the
synchronizer selection device 98 is shiftable to the left to engage the synchronizer
B2 and shiftable to the right to engage the synchronizer BR.
[0022] The back-to-back synchronizer pair C includes a synchronizer C5 and
a synchronizer C7. The synchronizer C5 is selectively engagable to connect the gear
62 for common rotation with the first countershaft 50. The synchronizer C7 is
selectively engageable to connect the gear 68 for common rotation with the first
countershaft 50. A single synchronizer selection device 100 is operable to control
engagement of both the synchronizers C5 and C7. Specifically, the synchronizer
selection device 100 is shiftable to the left to engage the synchronizer C5 and
shiftable to the right the engage the synchronizer C7.
[0023] The back-to-back synchronizer pair D includes a synchronizer D6
and a synchronizer D4. The synchronizer D6 is selectively engagable to connect the
gear 74 for common rotation with the first countershaft 50. The synchronizer D4 is
selectively the synchronizers D6 and D4. Specifically, the synchronizer selection
device 102 is shiftable to the left to engage the synchronizer D6 and shiftable to the
right to engage the synchronizer D4.
[0024] Referring to Figure 2, the engagement schedule of the shifting
friction clutches CO and CE as well as the synchronizers is shown. As indicated in
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Figure 2, seven forward gears (i.e., speed ratios) and a reverse gear (i.e., speed ratio)
are achieved. Those skilled in the art will recognize that the gears shown in Figure 1
may be designed with various tooth counts that, when the clutches and synchronizers
are engaged according to the truth table of Figure 2, will result in seven forward
speed ratios and a reverse speed ratio corresponding with the seven forward gears
and the reverse gear. For example, the following gear ratios may have different
numerical values: First gear: tooth count gear 64/tooth count gear 60; Second gear:
tooth count gear 76/tooth count gear 72; Third gear tooth count gear 70/tooth count
gear 66; Fourth gear: tooth count gear 80/tooth count gear 78; Fifth gear: tooth count
gear 62/tooth count gear 60; Sixth gear: tooth count gear 74/tooth count gear 72;
Seventh gear: tooth count gear 68/tooth count gear 66; Reverse gear: tooth count
gear 84/tooth count gear 78; First countershaft (50) output: tooth count gear 90/tooth
count gear 92. Second countershaft (52) output: tooth count gear 86/tooth count gear
88; The tooth counts are selected to achieve desired speed ratios, ratio steps, and
overall speed ratio.
[0025J To establish the reverse speed ratio, the clutch CE and the
synchronizer BR are engaged. By engagement of the clutch CE torque is transferred
from the input member 26 to the intermediate shaft 46. By engagement of the
synchronizer BR torque is transferred from the intermediate shaft 44 to the second
countershaft 52 via intermeshing gears 78, 82 and 84, with the gear 82 acting as an
idler gear so that the gear 84 rotates in the same direction as the gear 78. Torque is
transferred from the second countershaft 52 to the output member 56 via the
intermeshing gears 86 and 88.
[0026] To establish the first forward speed ratio, the input friction clutch CO
and the synchronizer Al are engaged. Torque is transferred from the input member
26 to the intermediate shaft 44 via engagement of the input shifting friction clutch
CO. Torque is transferred from the intermediate shaft 44 to the second countershaft
52 by engagement of synchronizer Al through the intermeshing gears 60 and 62.
Torque is transferred from the second countershaft 52 to the output member 56 via
intermeshing gears 86 and 88.
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[0027] To establish the second forward speed ratio, input friction shifting
clutch CE and the synchronizer B2 are engaged. Torque is transferred from the
input member 26 to the intermediate shaft 46 via engagement of clutch CE. Torque
is then transferred from the intermediate shaft 46 to the second countershaft 52 via
engagement of the synchronizer B2 through the intermeshing gears 72 and 76.
Torque is transferred from the second countershaft 52 to the output member 56 via
the intermeshing gears 86 and 88.
[0028] To establish the third forward speed ratio, the input friction shifting
clutch CO and the synchronizer A3 are engaged. Torque is transferred from the
input member 26 to the intermediate shaft 44 via engagement of the clutch CO.
Torque is transferred from the intermediate shaft 44 to the second countershaft 52
via engagement of the synchronizer A3 through the intermeshing gears 66 and 70.
Torque is transferred from the second countershaft 52 to the output member 56 via
the intermeshing gears 86 and 88.
[0029] It will thus be appreciated that all of the four lower speed (higher
numerical reduction ratios) gears (1st, 2nd, 3rd and Reverse) are disposed on the
second countershaft 52.
[0030] To establish the fourth forward speed ratio, the input friction shifting
clutch CE and the synchronizer D4 are engaged. Torque is transferred from the
input member 26 to the intermediate shaft 46 via engagement of the clutch CE.
Torque is transferred from the intermediate shaft 46 to the first countershaft 50 via
the engagement of synchronizer D4 through the intermeshing gears 78 and 80.
Torque is transferred from the first countershaft 50 to the output member 56 through
the intermeshing gears 90 and 92.
[0031] A fifth forward speed ratio is established by engagement of the input
friction shifting clutch CO and the synchronizer C5. Torque is transferred from the
input member 26 to the intermediate shaft 44 via engagement of the clutch CO.
Torque is transferred from the intermediate shaft 44 to the first countershaft 50 via
engagement of the synchronizer C5 through the intermeshing gears 60 and 62.
Torque is transferred from the first countershaft 50 to the output member 56 through
the intermeshing gears 90 and 92.
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[0032] A sixth forward speed ratio is established by engagement of the input
friction shifting clutch CE and the synchronizer D6. Torque is transferred from the
input member 26 to the intermediate shaft 46 via engagement of the clutch CE.
Torque is transferred from the intermediate shaft 46 to the first countershaft 50 via
engagement of the synchronizer D6 through the intermeshing gears 72 and 74.
Torque is transferred from the first countershaft 50 to the output member 56 through
the intermeshing gears 90 and 92.
[0033] A seventh forward speed ratio is established via engagement of the
input friction shifting clutch CO and the synchronizer C7. Torque is transferred
from the input member 26 to the intermediate shaft 44 via engagement of the input
friction shifting clutch CO. Torque is transferred from the intermediate shaft 44 to
the first countershaft 50 via engagement of synchronizer C7 through intermeshing
gears 66 and 68. Torque is transferred from the first countershaft 50 to the output
member 56 through the intermeshing gears 90 and 92.
[0034] It will thus also be appreciated that all of the four higher speed (lower
numerical reduction ratio) gears (4n, 5n, 6n and 7U) are disposed on the first
countershaft 50. This arrangement of higher speed gears on the first countershaft 50
and lower speed gears on the second countershaft 52 is facilitated by the difference
in center to center distances between the axes of the first and second countershafts
50, 52 and the common axis of the two intermediate shafts 44 and 46. In Figure 1,
this greater distance "X" between the axis of the second countershaft 52 and the
common axis of the two intermediate shafts 44 and 46 is illustrated and contrasted
with the smaller distance "Y" between the axis of the first countershaft 50 and the
common axis of the two intermediate shafts 44 and 46. This arrangement also
assists maintenance of reasonable torque and speed ratios on the ratio gears.
Distributing the overall gear state ratio, i.e., that overall gear ratio between the input
member 26 (or the intermediate shafts 44 and 46) and the output member 56,
between the ratio and transfer gearsets allows for smaller gear diameter packaging
than an arrangement that develops all the gear state ratios in one gearset.
[0035] Referring now to Figure 3, the torque converter 16, the pump 36, the
stationary clutch hub support member 40, the clutch hub 42 and the stator support
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shaft 38 are shown in greater detail. The transmission oil pump 36 is operatively
connected to the pump portion 22 of the torque converter 16 and to the engine output
member 23 via pump portion hub member 25. The stator portion 24 is operatively
connected to the stator support shaft 38 which is connected with the stationary clutch
hub support member 40. The transmission housing 30 is bolted or otherwise
connected with the stationary member clutch hub support member 40. Thus, the
pump 36 is radially-outward of the stator support shaft 38 and is radially-inward of
and supported by the stationary clutch hub support member 40.
[0036] The turbine portion 20 is operatively connected for rotation with the
input member 26. The input member 26 in turn is operatively connected for rotation
with the clutch hub 42. The clutch hub 42 supports a portion of the friction input
shifting clutches CO and CE. The friction input shifting clutch CO has another
portion operatively connected for rotation with the intermediate shaft 44. The
friction input shifting clutch CE has another portion operatively connected for
rotation with intermediate shaft 46. Engagement of the clutch CO connects the input
member 26 and the clutch hub 42 for rotation with the intermediate shaft 44.
Engagement of the clutch CE connects the input member 26 and the clutch hub 42
for rotation with the intermediate shaft 46.
[0037] Transmission oil from pump the 36 is routed to the torque converter
16 and to the friction shifting clutches CO and CE. Torque converter clutch apply
oil is routed from the pump 36 to the torque converter 16 via a sleeve passage 101
which is an annular passage between the pump portion sleeve shaft 103 and the
stator support shaft 38. The pump portion sleeve shaft 103 operatively connects the
pump portion 22 to the pump 36. Torque converter clutch release oil is also routed
to the torque converter 16 through a stator support shaft passage 104 in the stator
support shaft 38. The oil makes its way from the pump 36 to the stator support shaft
passage 104 through a horizontally running crevice 108 between the stationary
clutch hub support member 40 and the stator support shaft 38. Lubrication oil for
gears supported on the intermediate shafts 44 and 46 is delivered via a lubrication
passage 106.
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[0038] The stationary clutch hub support member 40 also has clutch hub
support member passages 110 and 112 formed therein to direct clutch apply oil from
the pump 36 via the horizontal crevice 108 to clutch hub passages 114 and 116. The
clutch hub 42 also has additional passages (not shown) in fluid communication with
one another for delivering dam oil to the clutches CO and CE. These additional dam
oil passages are located in a different radial plane than the passages 114 and 116.
The clutch hub passage 114 directs oil to the input friction clutch CE and the clutch
hub passage 116 directs oil to the input friction clutch CO.
[0039] The passage 118 is an oil supply to the pump 36 in the housing 30
and is fluidly communicable with a filter (not shown) through which oil is supplied
to the pump 36. Multiple valves, represented by a valve 120, control oil flow
through passages 101, 104, 106, 108, 110, 112, 114 and 116 and communicate with
one or more valve bodies (not shown).
[0040] Thus, the unique packaging of the oil pump 36 adjacent the clutch
hub 42 enables a relatively simple cooling circuit for the friction shifting clutches
CO and CE through the stationary clutch hub support member passages 110, 112
and the clutch hub passages 114, 116. During assembly of the transmission 18, the
clutch hub 42 is piloted over the stationary hub support member 40, which serves to
partially support both the clutch hub 42 and the pump 36.
[0041] While the best modes for carrying out the invention have been
described in detail, those familiar with the art to which this invention relates will
recognize various alternative designs and embodiments for practicing the invention
within the scope of the appended claims.
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CLAIMS
1. An automatic transmission for a motor vehicle, comprising, in
combination:
an input member;
a first and a second concentrically disposed intermediate shaft;
a first and a second friction clutch alternately selectively engageable
for operatively connecting said input member to said respective first and second
intermediate shafts;
a first and a second countershaft;
a first driving input gear coupled for rotation with said first
intermediate shaft and meshing with a first pair of driven input gears each
connectable for rotation with a respective one of said countershafts for transferring
torque to one of said countershafts when said first friction clutch is engaged;
a second driving input gear coupled for rotation with said second
intermediate shaft and meshing with a second pair of driven input gears each
connectable for rotation with a respective one of said countershafts for transferring
torque to one of said countershafts when said second friction clutch is engaged;
a third driving input gear coupled for common rotation with said firs I
intermediate shaft and meshing with a third set of driven input gears each
connectable for common rotation with a respective one of said countershafts for
transferring torque to one of said countershafts when said first friction clutch is
engaged; and
a fourth driving input gear coupled for common rotation with said
second intermediate shaft and meshing with a fourth set of driven input gears each
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conncctable for common rotation with a respective one of said countershafts for
transferring torque to one of said countershafts when said second friction clutch is
engaged.
2. The automatic transmission of Claim 1 further including
a torque converter having an input and an output driving said input member.
3. The automatic transmission of Claim 1 further including a
plurality of synchronizers operatively disposed between said driven input gears and
said countershafts.
4. The automatic transmission of Claim 1 wherein higher speed gears are
associated with said first countershaft.
5. The automatic transmission of Claim 4 wherein said higher speed
gears arc fourth, fifth, sixth and seventh.

6. The automatic transmission of Claim 1 wherein said lower speed gears
are associated with said second countershaft.
7. The automatic transmission of Claim 6 wherein said lower speed
gears arc first, second, third and reverse.
8. The automatic transmission of Claim 1 wherein a spacing between an
axis of said intermediate shafts and said countershaft associated with said lower
speed gears is greater than a distance between said axis and said countershaft
associated with said higher speed gears.
9. An automatic transmission for a motor vehicle comprising, in
combination:
an input member;
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first and second concentrically disposed intermediate shafts;
first and second selectively engageable friction clutches for coupling
said input member to one of said first and said second intermediate shafts;
first and second countershafts;
a first plurality of meshing gear pairs, one of each said first pairs of
gears disposed for free rotation about said first countershaft and another of each of
said first pairs of gears coupled to one of said intermediate shafts;
a first plurality of sychronizers for selectively and exclusively
coupling said one of said first pairs of gears to said first countershaft,
a second plurality of meshing gears pairs, one of each of said second
pairs of gears disposed for free rotation about said second countershaft and another
of each of said second pairs of gears coupled to one of said intermediate shafts; and
a second plurality of sychronizers for selectively and exclusively
coupling said one of said second pairs of gears to said second countershaft, and
wherein said first plurality of meshing gears provide lower speed
gear ratios and said second plurality of gears provide higher speed gear ratios.
10. The automatic transmission of Claim 9 wherein said lower speed gear
ratios are first, second, third and reverse and said higher speed gear ratios are fourth,
fifth, sixth and seventh.
11. The automatic transmission of Claim 9 wherein a distance
between said first countershaft and an axis of said intermediate shafts is greater than
a distance between said second countershaft and said axis.
12. The automatic transmission of Claim 9 further including a torque
converter having an input and an output driving said input member.
13. The automatic transmission of Claim 12 further including an
engine having an output driving said input of said torque converter.
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14. The automatic transmission of Claim 9 including eight pairs of
said meshing gears providing seven forward gear ratios and a reverse gear ratio.
15. An automatic transmission for a motor vehicle comprising, in
combination,
a torque converter having an input and an output;
first and second concentrically disposed intermediate shafts;
first and second friction clutches alternately selectively cngageable
for coupling said output of said torque converter to one of said first and second
intermediate shafts;
first and second countershafts;
a first plurality of meshing gear pairs, one of each said first pairs of
gears disposed for free rotation about said first countershaft and another of each of
said first pairs of gears coupled to one of said intermediate shafts,
a first plurality of sychronizers for selectively and exclusively
coupling said one of said first pairs of gears to said first countershaft;
a second plurality of meshing gears pairs, one of each of said second
pairs of gears disposed for free rotation about said second countershaft and another
of each of said second pairs of gears coupled to one of said intermediate shafts; and
a second plurality of sychronizers for selectively and exclusively
coupling said one of said second pairs of gears to said second countershaft,
said first plurality of meshing gears providing higher speed gear
ratios and said second plurality of gears providing lower speed gear ratios.
16. The automatic transmission of Claim 15 wherein said lower
speed gear ratios are first, second, third and reverse and said higher speed gear
ratios arc fourth, fifth, sixth and seventh.
17. The automatic transmission of Claim 15 wherein a distance between
said first countershaft and an axis of said intermediate shafts is less than a distance
between said second countershaft and said axis.
17

17. The automatic transmission of Claim 15 further including an
engine having an output driving said input of said torque converter.
18
19. The automatic transmission of Claim 15 including eight pairs of
said meshing gears providing seven forward gear ratios and reverse.

A powertrain having a torque converter, friction input shifting clutches and
shared driving gears has an axially compact design, packages a transmission pump
between the torque converter and a clutch hub and achieves seven forward speed
ratios utilizing four back-to-back synchronizers.

Documents:

00265-kol-2008-abstract.pdf

00265-kol-2008-claims.pdf

00265-kol-2008-correspondence others.pdf

00265-kol-2008-description complete.pdf

00265-kol-2008-drawings.pdf

00265-kol-2008-form 1.pdf

00265-kol-2008-form 2.pdf

00265-kol-2008-form 3.pdf

00265-kol-2008-form 5.pdf

00265-kol-2008-priority document.pdf

265-KOL-2008-(05-03-2013)-ABSTRACT.pdf

265-KOL-2008-(05-03-2013)-ANNEXURE TO FORM-3.pdf

265-KOL-2008-(05-03-2013)-CLAIMS.pdf

265-KOL-2008-(05-03-2013)-CORRESPONDENCE.pdf

265-KOL-2008-(05-03-2013)-DESCRIPTION (COMPLETE).pdf

265-KOL-2008-(05-03-2013)-DRAWINGS.pdf

265-KOL-2008-(05-03-2013)-FORM-1.pdf

265-KOL-2008-(05-03-2013)-FORM-2.pdf

265-KOL-2008-(05-03-2013)-OTHERS.pdf

265-KOL-2008-(05-03-2013)-PA.pdf

265-KOL-2008-(05-03-2013)-PETITION UNDER RULE 137.pdf

265-KOL-2008-ASSIGNMENT.pdf

265-KOL-2008-CORRESPONDENCE OTHERS 1.1.pdf

265-kol-2008-form 18.pdf

abstract-00265-kol-2008.jpg


Patent Number 258118
Indian Patent Application Number 265/KOL/2008
PG Journal Number 49/2013
Publication Date 06-Dec-2013
Grant Date 04-Dec-2013
Date of Filing 15-Feb-2008
Name of Patentee GM GLOBAL TECHNOLOGY OPERATIONS, INC.
Applicant Address 300 GM RENAISSANCE CENTER DETROIT, MICHIGAN
Inventors:
# Inventor's Name Inventor's Address
1 JAMES B. BORGERSON 2928 SILVER SPRING DRIVE ANN ARBOR, MICHIGAN 48103-8913
2 SIMON P FITZGERALD 5 WANAARING TCE GLENWOOD, NEW SOUTH WALES 2768
PCT International Classification Number F16H3/44
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11/680,657 2007-03-01 U.S.A.